package com.my.cd.facade;

/**
 * 家庭影院设备类：屏幕
 */
public class Screen {

    private static Screen instance = null;

    private Screen() {
    }

    public static Screen getInstance() {
        if (instance == null) {
            instance = new Screen();
        }
        return instance;
    }

    public void up() {
        System.out.println("Screen  up");
    }

    public void down() {
        System.out.println("Screen  down");
    }

}
